Most organizations have a data center for running those applications that handle the core business and operational data of the organization. Also referred to a server room, computer closet, or network operations center, a data center has various computing resources that support the basic intranet and Internet services needed by users within the organization, such as email servers, proxy servers, and DNS servers. In addition, data centers typically deploy network security components, such as firewalls, VPN (virtual private network) gateways, and intrusion detection systems.
In traditional networking, routers and switch devices usually refer to a MAC (Media Access Control) address, to a VLAN (Virtual Local Area Network) identifier, or to zoning information within a given frame to forward that frame. This forwarding behavior limits addressing to one other system (i.e. the next hop in the path toward the frame's destination). In a data center environment, such frame forwarding behavior can impact performance.
FIG. 1 illustrates frame forwarding behavior in a conventional data center environment 10 having a switch device 12 connected through a first port 14-1 to a first computing system 16 (here, called an initiating system), through a second port 14-2 to a second computing system 18, and through a third port 14-N to a third computing system 20. Consider that the initiating system has a frame that is to be processed by the second and third computing systems. The initiating system 16 sends (step 1) a frame to the switch device 12 over link 22. The switch device 12 forwards (step 2) the frame through the second port 14-2 to the second computing system 18 over link 24. After the second computing system completes its processing of the frame, the frame returns (step 3) to the switch device 12 through the second port 14-2 over link 24. The switch device 12 then returns (step 4) the frame to the initiating system 16 through the first port 14-1 over link 22.
On receiving the frame from the switch device 12, the initiating system 16 sends (step 5) the frame back to the switch device 12 over link 22, this time for processing by the third computing system 20. The switch device 12 forwards (step 6) the frame to the third computing system 20 through the third port 14-N over link 26. The third computing system 20 completes its processing of the frame and returns (step 7) the frame to the switch device 12 over link 26. The switch device 12 then returns (step 8) the frame to the initiating system 16 over link 22.
A disadvantage of such frame forwarding is the amount of frame traffic traversing the link 22 between the initiating system 16 and the switch device 12. In this simple illustration, this link 22 handles twice the traffic load of that handled by each of the other links 24, 26 to the other computing systems 18, 20. This traffic load multiplies with each additional computing system involved the frame processing sequence. Accordingly, for many types of data center transactions, the link can become a bottleneck on performance.